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Simultaneous Measurement of Intracrystalline Diffusion in Molecular Sieve Zeolites by NMR and Gravimetric Methods

用核磁共振和重量分析法同时测量分子筛沸石中的晶内扩散

基本信息

批准号：
8700022
负责人：
Yi Ma
金额：
$ 13.74万
依托单位：
Worcester Polytechnic Institute
依托单位国家：
美国
项目类别：
Continuing Grant
财政年份：
1987
资助国家：
美国
起止时间：
1987-03-01 至 1990-02-28
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=8700022&HistoricalAwards=false
关键词：
Simultaneous Measurement Intracrystalline Diffusion Molecular

项目摘要

Research Summary: The diffusive and adsorptive properties of hydrocarbons on high-silica zeolites are investigated by gravimetric and NMR methods to resolve the differences in diffusion measurements, which are reported in the literature to be of several orders of magnitude between measurements made by these two techniques, in order to gain fundamental understanding of diffusion in zeolites. Novelty: A new apparatus is being constructed and will be used to make simultaneous diffusion measurements of identical zeolite samples, activated under exactly the same conditions, under identical sorbate pressure, using NMR and gravimetric methods. This unique method of measurement will make it possible to compare the results from microscopic NMR measurements to those from macroscopic gravimetric measurements, thus resolving currently existing large differences. Technical Impact: The information obtained from the proposed work will not only provide fundamental understanding of the transport and adsorption properties of zeolites but also will be of importance in improving engineering design in such important operations as purification of gas streams, separation processes, and catalytic conversion units. A better understanding of the diffusion mechanisms and equilibrium properties can provide valuable information in understanding catalytic behavior of shape-selective zeolites used in practical industrial applications such as xylene isomerization, dewaxing and conversion of methanol to gasoline.

研究摘要：通过重量分析和核磁共振方法研究碳氢化合物在高硅沸石上的扩散和吸附特性，以解决扩散测量的差异（文献报道这两种技术测量之间存在几个数量级的差异），以获得对沸石扩散的基本了解。新颖性：正在建造一种新设备，将用于使用核磁共振和重量分析方法，在完全相同的条件下、相同的吸附压力下激活相同的沸石样品，同时进行扩散测量。这种独特的测量方法将使微观核磁共振测量结果与宏观重力测量结果进行比较成为可能，从而解决目前存在的巨大差异。技术影响：从拟议工作中获得的信息不仅可以提供对沸石的传输和吸附特性的基本了解，而且对于改进气流净化、分离过程和催化转化装置等重要操作中的工程设计也具有重要意义。更好地了解扩散机制和平衡特性可以为理解实际工业应用（例如二甲苯异构化、脱蜡和甲醇转化为汽油）中使用的择形沸石的催化行为提供有价值的信息。